Amine-based CO2 capture aided by acid-basic bifunctional catalyst: Advancement of amine regeneration using metal modified MCM-41

Abstract

The most critical challenge for the industrial implementation of amine solution CO₂ capture is the high heat duty of rich solvent thermal regeneration. Despite significant efforts to lower energy consumption, including employing new amine solvents and process intensification, a novel approach of overcoming this challenge is still demanded. Here, we introduce a novel acid-basic bifunctional catalyst system to reducing the regeneration heat duty by adding metal modified MCM-41 catalyst into amine-based solution. MCM-41 was modified with three metals (Fe, Al, Mo) as well as with different Fe content for catalysis of the rich monoethanolamine (MEA) solvent regeneration process at 98 °C. Results reveal that all the catalysts accelerated regeneration process, and Fe₂O₃ modified MCM-41 (MFe) catalysts exhibited superior catalytic performance. Notably, the addition of MFe greatly improved the CO₂ desorption performance (desorption factor) to 206.3–337.1% compared to the catalyst-free run. The excellent catalytic performance of MFe is ascribed to its improved Brϕnsted acid sites and increased basic sites. Additionally, MFe showed good cyclic stability and its use in the regeneration process enhanced the subsequent CO₂ absorption performance. Furthermore, a plausible dual sites mechanism of catalytic amine solvent regeneration over MFe was proposed. Our results demonstrate that the acid-basic bifunctional catalyst plays significant role in developing the amine-based post-combustion CO₂ capture technology and has important promise for real-world application.